The present invention relates to a method of and a device for estimating motions in a sequence of pictures. Such a method is essentially applicable in the field of digital signal processing, for information compression, picture quality improvement, target tracking, etc. and, for example, in digital picture coding devices for the reduction of the rate of information to be transmitted or to be registered when, for example, magnetoscopes are concerned.
The article by A.N. Netravali and J.D. Robbins "Motion-Compensated Television Coding: Part I" published in the magazine "The Bell System Technical Journal", vol 58, no. 3, March 1979 describes a motion estimation method providing essentially for performing a classification of picture elements in fixed elements and moving elements and for estimating the motions by means of an adaptive prediction method utilizing elements of a preceding picture for comparing them in position and luminosity with those of the current picture. Yet, this method has considerable drawbacks. On the one hand, as far as the motion is concerned, it does not take into account the correlation between neighboring elements. Moreover, in the classification carried out, the influence of the classification relative to given picture elements on that of the following elements is not examined.